Study On The Aerodynamic Performance Of A Wind Turbine Blade And The Fluid-structure Interaction Of Horizontal Axis Wind Turbine For Plateau Area

China is rich in wind resources,and there is a broad prospect for the application.As the critical equipment for wind power,although many domestic and abroad scholars have been done study in depth on the aerodynamic performance of wind turbine blades,and have achieved fruitful results.But the calculation for the aerodynamic performance of wind turbine blades and wind turbine still have many problems,such as static stall problem,dynamic stall problem,three-dimensional rotational effect problem and so on,at the same time,the problems like the dynamic characteristics and the vibration of the wind turbine induced by wind are relatively few studies.The research was carried out in this paper combined with the aero-dynamic performance of the wind turbine blades and the fluid-structure coupling,mainly included the following six aspects:(l)Using the CFD software FLUENT,the steady and unsteady numerical analysis method were relatively adopted,the NACA0018 air-foil developed by USA National Aviation Advisory Committee was analyzed detailed,the characteristics of the lift coefficient and drag coefficient of airfoil were studied,at the same time,the structure of flow field was analyzed,the turbulence model and near-wall mesh density which were applied to numerical simulation of wind turbine airfoil was systematically discussed.According to the condition that NACA-0018 airfoil would be in flow separation state with the different wind velocity,the static stall characteristics of NACA0018 airfoil under different conditions were obtained.(2)With the application of user defined functions,combined the k-co SST turbulence model with the dynamic mesh technique,the un-steady flow field numerical simulation study for NACA0018 airfoil harmonic oscillation was carried out,the results showed that the transient flow characteristics of the harmonic oscillation for NACA0018 airfoil can be obtained in this combination,and the turbulent flow field had a strong ability to simulate the harmonic oscillation for airfoils.The dynamic stall characteristics of NACA0018 airfoil with the changes of the vibration amplitude and the reduced frequency were revealed.(3)The large eddy simulation(LES)and advanced sliding mesh technology were applied to a 750 plateau horizontal axis wind turbine,the numerical simulation of three-dimensional transient turbulent flow field for the wind turbine considered with the vibration and the static or dynamic interference was successful realized.The results showed that the large eddy simulation can obtain the transient flow characteristics of wind turbines,also has a strong ability to simulate the turbulent flow field for a wind turbine.The whole flow field dynamic characteristics and the distribution characteristics of flow structure for the wind turbine flow past a wedge were revealed,the law of the turbine blade stall and the interaction between blade rotation and tower structure were obtained.Through the study of the wind turbine torque,the efficiency of wind turbine was obtained.(4)The calculation model of a wind turbine for plateau area including blade,hub,nacelle,tower,foundation and soil is established,the structural dynamic analysis is done,and then the natural frequency and vibration mode of the wind turbine tower are obtained.Comparing it with the results obtained by analytical method,based on the verified accuracy of the models,studied coupling problem tower vibration induced by the turbine vibration for two working conditions of starting the turbine to normal rotation and the normal turbine rotation,and the frequency of the wind turbine structure resonance value induced by wind turbine start process was obtained.(5)Constructed a simple and efficient fluid solid unidirectional coupling method for the wind turbine,and self-designed the corresponding program,realized the accurate inputting the dynamic flow field calculation results into the solid model.Took a 750 plateau type wind turbine as the research object,studies the dynamic response problem for the flexible tower vibration induced by wind under fluid solid coup-ling condition.(6)Took a 750 plateau type wind turbine as the object of study,dynamic test in site was carried out,the first-order natural frequency and the dynamic strain value of tower was gotten,then according to Hooke’s law,the maximum dynamic stress of the tested point was obtained,the test results were in good agreement with the results of numerical simulation.